Cosmological validation of low-metallicity galactic winds

Determine whether the low-metallicity winds used in the Auriga galaxy formation model arise in fully cosmological simulations that resolve multiphase feedback-driven outflows and their propagation through an evolving circumgalactic medium, and directly compare their outflow metallicities with those adopted in the simulations.

Background

The study uses an effective wind prescription with metal-depleted winds, but does not identify the physical mechanism that produces such winds. The discussion considers several possibilities, including winds launched above the disc plane, cosmic-ray-driven outflows, and multiphase outflows in which most of the mass is carried by cool gas while newly synthesized metals remain in a hot phase.

Existing supporting studies use idealized or isolated environments and therefore do not establish whether the adopted low wind metallicities occur when feedback operates in a fully cosmological setting. The unresolved task is to compare outflow metallicities directly and test them in simulations containing a multiphase, evolving circumgalactic medium.